2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Endocrine, Nutritional And Metabolic Diseases, And Immunity Disorders 240-279 > Diseases Of Other Endocrine Glands 250-259 > Diseases Of Thymus Gland 254.* > 2006 ICD-9-CM Diagnosis 254.0 Persistent hyperplasia of thymus View the most recent version of ICD-9-CM 254.0 Enlargement of the thymus. A condition described in the late 1940's and 1950's as pathological thymic hypertrophy was status thymolymphaticus and was treated with radiotherapy. Unnecessary removal of the thymus was also practiced. It later became apparent that the thymus undergoes normal physiological hypertrophy, reaching a maximum at puberty and involuting thereafter. The concept of status thymolymphaticus has been abandoned. Thymus hyperplasia is present in two thirds of all patients with myasthenia gravis. 254.0 is a specific code that can be used to specify a diagnosis 254.0 contains 4 index entries View the ICD-9-CM Volume 1 254.* hierarchy Alternate Terminology Hypertrophy of thymus  Index entries containing 254.0: Enlargement, enlarged - see also Hypertrophy thymus (congenital) (gland) 254.0 Hyperplasia, hyperplastic thymus (gland) (persistent) 254.0 Hypertrophy, hypertrophic thymic, thymus (congenital) (gland) 254.0 Persistence, persistent (congenital) 759.89 thymus (gland) 254.8 hyperplasia 254.0